Intraocular lenses are usually injected into the aphakic eye in a folded state and there they unfold within a matter of seconds. In some cases, anterior chamber intraocular lenses are also injected into the phakic eye. The optical properties of the patient eye are usually measured before and after the surgical procedure. Thus, the medical practitioner obtains no information during the operation with respect to whether the inserted lens can also in actual fact enable the desired visual performance of the patient eye.
Hence, it would be desirable to determine the optical properties of the patient eye with the intraocular lens during surgery. However, such a measurement proves impossible using conventional methods because a number of interfering factors occur during surgery, and these falsify the measurement result. One source of error during the measurement lies in the fact that the optical properties of the intraocular lens change over a period of time of at least fifteen minutes after the injection into the patient eye, during which the intraocular lens completely unfolds. An intraoperative measurement performed within a few minutes after the injection would be falsified as a result of this. Since conventional cataract surgery only takes approximately five to ten minutes, it however proves not to be possible to wait in the case of the intraoperative measurement of an implanted intraocular lens until the optical properties have reached their final value.
DE 10 2007 017 599 A9 describes a method for measuring geometric parameters of an eye in order to determine a fitting intraocular lens, for example also for an eye which, as a result of preceding refractive corneal surgery, has modified relationships between the front side of the cornea and the back side of the cornea.
U.S. Pat. No. 7,476,248 and U.S. patent application publication 2009/0079935 describe a method for predicting changes in the patient eye caused by the operation. Here, changes of the eye, for example, a deformation of the cornea as a result of the incisions performed during the operation, are used in the calculation of the optical properties of the intraocular lens.
U.S. Pat. Nos. 8,437,008 and 7,982,881 describe a device for measuring a sample, more particularly an eye, by interferometry.
U.S. patent application publication 2009/0069794 describes an instrument for laser eye surgery, wherein the surgical laser beam is focused as accurately as possible onto the target tissue.